Observation of Enhanced Chiral Asymmetries in the Inner-Shell Photoionization of Uniaxially Oriented Methyloxirane Enantiomers.

Most large molecules are chiral in their structure: they exist as two enantiomers, which are mirror images of each other. Whereas the rovibronic sublevels of two enantiomers are almost identical (neglecting a minuscular effect of the weak interaction), it turns out that the photoelectric effect is sensitive to the absolute configuration of the ionized enantiomer. Indeed, photoionization of randomly oriented enantiomers by left or right circularly polarized light results in a slightly different electron flux parallel or antiparallel with respect to the photon propagation direction-an effect termed photoelectron circular dichroism (PECD). Our comprehensive study demonstrates that the origin of PECD can be found in the molecular frame electron emission pattern connecting PECD to other fundamental photophysical effects such as the circular dichroism in angular distributions (CDAD). Accordingly, distinct spatial orientations of a chiral molecule enhance the PECD by a factor of about 10.

Systematic study of the structure-property relationships of branched hierarchical TiO2/ZnO nanostructures.

We report a simple and effective route for fabricating branched hierarchical nanostructures of TiO(2)/ZnO by combining electrospinning and the low-temperature hydrothermal growth technique. First, TiO(2) nanofibers were prepared by electrospinning polystyrene (PS)/titanium tetraisopropoxide (Ti(OiPr)(4)) solutions onto glass substrates followed by calcination at 500 °C. The electrospun TiO(2) nanofibers served as a 3D primary platform upon which the branched, highly uniform, and dense secondary ZnO nanorods were hydrothermally grown. We observed that the concentration of Ti(OiPr)(4) in the polystyrene solution has a significant effect on the surface roughness and areal material ratio of the electrospun fibers. Most significantly, the morphology of the branched secondary ZnO nanorods and the overall charge transfer capacity of the nanoheterostructured systems are controlled by the density of the TiO(2) platform. This study demonstrates that, by properly choosing the synthesis parameters, it is possible to fine-tune the microscopic and macroscopic properties of branched hierarchical metal-oxide systems. The presented approach can be applied to the development of controlled, reproducible, miniaturized, and robust high-performance metal-oxide photovoltaic and photocatalytic systems.

Identification of possible candidate genes regulating Sjögren's syndrome-associated autoimmunity: a potential role for TNFSF4 in autoimmune exocrinopathy.

INTRODUCTION: Sjögren syndrome (SjS) is a systemic autoimmune disease in which an immunological attack primarily against the salivary and lacrimal glands results in the loss of acinar cell tissue and function, leading to stomatitis sicca and keratoconjunctivitis sicca. In recent years, two genetic regions, one on chromosome 1 (designated autoimmune exocrinopathy 2 or Aec2) and the second on chromosome 3 (designated autoimmune exocrinopathy 1 or Aec1) derived from nonobese diabetic (NOD) mice, have been shown to be necessary and sufficient to replicate SjS-like disease in nonsusceptible C57BL/6 mice. METHODS: Starting with the SjS-susceptible C57BL/6-derived mouse, referred to as C57BL/6.NOD-Aec1Aec2, we generated a large set of recombinant inbred (RI) lines containing portions of Aec2 as a means of identifying more precisely the genetic elements of chromosome 1 responsible for disease development. RESULTS: Disease profiling of these RI lines has revealed that the SjS susceptibility genes of Aec2 lie within a region located at approximately 79 +/- 5 cM distal to the centromere, as defined by microsatellite markers. This chromosomal region contains several sets of genes known to correlate with various immunopathological features of SjS as well as disease susceptibility genes for both type 1 diabetes and systemic lupus erythematosus in mice. One gene in particular, tumor necrosis factor (ligand) superfamily member 4 (or Ox40 ligand), encoding a product whose biological functions correlate with both physiological homeostasis and immune regulations, could be a potential candidate SjS susceptibility gene. CONCLUSIONS: These new RI lines represent the first step not only in fine mapping SjS susceptibility loci but also in identifying potential candidate SjS susceptibility genes. Identification of possible candidate genes permits construction of models describing underlying molecular pathogenic mechanisms in this model of SjS and establishes a basis for construction of specific gene knockout mice.